Cantilever loading extensible drawer rail



SheerI l of 2 INVENTOR. day/V /f ATTORNEYS March 4, 1969 CAN'TI'JEV'R LOADING EXTENSIBLE DRAWER RAIL Filed oct. 18, 1965 Q S N um x ,lfm D N\ Nm \0\ \Q%l O N Q NRJ .w LT1 l l i s 1 JNM@ i |i JM #Mi i Il if l U1 K ii, .n 4 E a .L

J. PIPE March 4, 1969 Z of 2 Sheet Filed Oct. 18, 1965 IJ I 1I I \\FIWMI I I I I I IQI%\IHIM I I NI NMI@ I I Im QWNMIIII I@ c a I .IFI II IIRII II. I W .II I I III I, I IImI`I`I Il s I I I I I IIIII I I IIII IHwh-I l-\ III. ll. Il.. II.. NIM. .Inl MII IMI IM III: INIIIIIXI I IN IIN: III MII .WIM HI NI II I .w NS N\\\ ATTORNEYS United States Patent O 3,431,042 CANTILEVER LOADING EXTENSIBLE DRAWER RAIL John Pipe, Grand Rapids, Mich., assignor to Steelcase, Inc., Grand Rapids, Mich., a corporation of Michigan Filed Oct. 18, 1965, Ser. No. 497,266 U.S. Cl. 312--339 6 Claims Int. Cl. A47b 88/10 ABSTRACT OF THE DISCLOSURE Drawer supporting and straddling rail assemblies achieving excellent retained alignment between the rails in the individual assemblies due to both vertical and lateral compressive loading on each of the individual balls between the rails, such compressive loading resulting from the torsional force applied with unique cantilever loading of the assembly, this cantilever loading being accomplished by the drawer rail having specially arranged and oriented cantilever loading portions.

This invention relates to drawer rail assemblies, and more particularly to telescoping drawer rail assemblies having unique cantilever loading action on the rails to achieve and retain optimum alignment between the rails.

Conventionally, each of the two slide rail assemblies employed in mirror image position on opposite sides of a drawer, between the drawer and the cabinet or case, includes telescopically intertting rails allowing extension therebetween for drawer extension and retraction. Minimum friction is normally obtained by the use of rolling ele-ments such as rollers or balls between the rails. Typically, a rail assembly includes a case rail for mounting to the inside wall of a cabinet, a drawer rail for mounting to the outer wall of a drawer, and an intermediate rail telescopically mounted between the drawer rail and the case rail, and allowing relatively `full extension of the drawer rail and the drawer attached thereto. If desired, a progressive propulsion roller may be mounted on the intermediate rail for contact on its periphery directly with both the case rail and the drawer rail. This roller can have a vertical or a horizontal axis.

lGenerally, the support between the rails is achieved by a rst plurality of balls retained between the case rail and the intermediate rail, and a second plurality of balls retained lbetween the intermediate rail and the drawer rail. This basic known structure effectuates a fairly good limited friction suspension assembly. Such a structure has shortcomings however, with a well known one being the difficulty of keeping the slides aligned vertically when the drawer is under load. This causes scraping contact between the rails themselves, thereby increasing the friction, and consequently increasing the operating force required to extend and retract them, as well as increasing the noise level. The conventional struct-ure also allows considerable side sway of the opened drawer and extended rail assemblies, due to clearance between the rails. Care must be taken to mount the rail assemblies exactly on a horizontal plane, or else rail rubbing etc. will normally occur constantly.

These drawbacks basically are due to the off-center loading of the drawer load with respect to the drawer .straddling, drawer rail assemblies. Eiforts to improve the structural characteristics have included those to control the lateral movement of the balls by controlling the manufacturing tolerances of the rail members to very critical values, or alternatively by slightly concavely curving the upper and lower -ball track surfaces on the rails. Control of tolerances has a very real practical limit however, and is only partially effective anyway. The concave ice dishing of the upper and lower track surfaces, although an improvement, is also definitely limited by the narrow breadth of the tracks, so that it is only partially eifective in actual practice. Both of these techniques also require considerable added manufacturing cost.

It is an object of this invention to provide a unique drawer rail assembly that uniquely employs cantilever loadnig to constantly retain the rails in optimum alignment.

Another object of this invention is to provide a drawer rail assembly achieving excellent rail alignment under load, resulting in an extremely small and inconsequential side sway of the drawer and assembly, even at full extension of the rail assembly. Moreover this is achieved without special close tolerances for rail parts, and without complicated dishing of the rail track surfaces.

Another object of this invention is to provide a novel cantilever loading drawer rail assembly that eliminates the direct scraping tendency between the rail members themselves, even when approaching full extension. The unit is therefore extremely quiet in operation, and has minimum friction.

Another object of this invention is to provide a drawer rail assembly achieving practically friction-free movement by unique loading of the individual balls on a vertical axis through each ball and also on a horizontal axis thlough the ball, with these axes being normal to each ot er.

Another object of this invention is to provide a drawer rail assembly having unique cantilever loading of the assembly in a manner to effect both vertical and lateral loading on the individual balls, on directly opposed bearing surfaces so that friction-free travel results, with constant vertical rail alignment, without lateral movement or sway, and without necessitating close tolerances.

Another object of this invention is to provide a drawer rail assembly that achieves smooth quiet action even if not mounted exactly on a horizontal plane, and in fact enabling the drawer to be mounted even on angles of up to about 45, yet without rail scraping, side sway, and the like.

These and several other objects of this invention will become apparent upon studying the following specification in conjunction with the drawings in which:

FIG. 1 is a side elevational view of the first form of the drawer rail assembly, shown in its retracted condition;

FIG. 2 is a side elevational view of the assembly in FIG. 1, shown extended;

FIG. 3 is an enlarged sectional View of the assembly in FIG. 1, taken on plane III-III;

FIG. 4 is a side elevational view of a second form of the novel drawer rail assembly, shown in a retracted condition;

FIG. 5 is a side elevational view FIG. 4, .shown extended; and

FIG. 6 is an enlarged sectional view of the assembly in FIGS. 4 and 5, taken on plane VI-VI of FIG. 4.

The term inwardly when used herein, refers to a direction toward the drawer to be mounted, and away from the case panel. The term outwardly means the opposite. lt will be realized that although one drawer rail assembly is shown in each form of the invention, a mirror image form will normally be employed in mirror image relationship to this drawer rail assembly. Since these are exactly alike except in mirror image, only one is specifically shown and described.

Referring now specifically to the drawings, the first drawer rail assembly 10 illustrated in FIGS. 1-3 includes a case rail 12, an intermediate rail 14, and a drawer rail 16.

Case rail 12 has an elongated, vertically oriented back of the assembly in panel for mounting to the inside vertical wall of a cabinet or case into which the drawer is to extend. Integral with this panel is a horizontally inwardly extending upper panel leg 22, from which depends a flange 24 extending downwardly parallel to panel 20 and terminating short of intermediate rail 14. Case rail 12 also includes a bottom horizontally inwardly extending leg panel 26 parallel to panel 22, and nor-mal to back panel 20, with a lower, depending, downwardly extending ange 28 integral therewith at its outer edge.

Telescopically intertting within case rail 12 is intermediate rail 14. This intermediate rail includes a main elongated vertical panel 30, having an inwardly extending horizontal upper ange 32. Welded to this ange is a Z- shaped member that includes a horizontal leg 34 secured to panel 32, an inner downwardly extending ange 36, parallel with back panel 20, and an upwardly extending outer flange 38 adjacent panel 20 and parallel to, opposite to flange 24 of case rail 12. Near to but spaced from the bottom ange 26 of case rail 12, intermediate rail 14 has a horizontally inwardly, extending panel 40, a downwardly depending retaining panel 42 extending therefrom and parallel to back panel 20, and preferably a horizontally extending panel 44 integral with portion 42.

Drawer rail 16 interfits telescopically in intermediate rail 14. It includes a retaining panel S0 extending vertically, i.e. parallel to panel 20, an outwardly extending horizontal panel 52 extending therefrom, and a vertically extending panel 54 extending up from panel 52 inside case rail 14 and parallel to its back panel 30. This drawer rail also includes an important horizontally extending cantilever loading leg 56 extending inwardly from panel 50, and in fact from the entire drawer rail assembly to form a loading platform.

Briefly therefore, case rail 12 is basically C-shaped in cross section, but having a pair of downwardly extending inner flanges, both extending in the `same direction, from the two legs of the C. Basically, the drawer rail 16 is double L-shaped, with one L being attached to and depending from the first L. Intermediate rail 14 has a C- shaped central portion, with an L-shaped depending p0rtion attached to its lower leg, and a Z-shaped member mounted to the top of its upper leg.

These three rails in the first form of the invention basically define four raceways to receive oating spherical balls. Each raceway preferably includes two spherical balls. Upper raceway 60 has opposite horizontal upper and lower bearing surfaces 22 and 34 of the case rail and intermediate rail, and has opposite vertical side bearing surfaces 38 and 24, all arranged in a square configuration to abut the retained balls on both a vertical axis and a horizontal axis. The next lower raceway 66 also has opposite upper and lower surfaces 32 and 52 of the intermediate rail and drawer rail, and opposite side surfaces 54 and 36 of the drawer rail and intermediate rail. The third raceway 72 has opposite upper and lower surfaces 52 and 40 of the drawer rail and intermediate rail and opposite side surfaces and 30 of the drawer rail and intermediate rail. The fourth and lowermost raceway 78 has opposite upper and lower surfaces 40 and 26 of the intermediate rail and case rail and opposite side surfaces 20 and 42 of the case rail and intermediate rail. Thus, each raceway is square, has four bearing surfaces. One vertical and one horizontal bearing surface are of one rail and the other vertical and horizontal surfaces are of another rail. Raceway between the intermediate rail and the case rail confines balls 62 and 62', raceway 66 between the top of the drawer rail and the intermediate rail connes balls 68 and 68', raceway 72 between the bottom of the drawer rail portion and the intermediate rail includes balls 74 and 74', and raceway 78 between the bottom of the case rail and the bottom of the intermediate rail includes balls and 80. The balls are each retained in their intended section of their raceways by suitable stops formed in conventional fashion as by depressing dimples e.g. 61 (FIG. 1) into the rail member astraddle each ball. Since this is conventional, such stops are not described in detail.

When the assemblies are fully assembled, each squareshaped raceway has width and height dimensions equal to the diameter of the spherical oating balls contained therein. Each ball is contracted on a vertical load axis with bearing surfaces which are directly opposed, and on a horizontal load axis on each side thereof against bearing surfaces which are directly opposed. Hence, when the load is applied to the structure in FIG. 3, with insertion of a drawer (not shown in FIG. 3) `between rail assembly 10 and its counterpart rail assembly arranged in mirror image to it on the opposite side of the drawer, the individual rails of assembly 10 will shift laterally and vertically under the cantilever load to take up the slack space shown adjacent the balls in FIG. 3. The two axesy of load, vertical and laterally horizontal, are normal to each other.

The rail assembly illustrated in FIGS. 1 through 3 may be readily assembled by inserting the intermediate rail into the case rail, with the floating ball members positioned therebetween, and by inserting the drawer rail into the intermediate rail, with the balls positioned therebetween. The intermediate rail may be securely positioned with respect to the case rail to prevent them from normally being accidentally disassembled as by a small flange retainer member 86 secured to a horizontal ange 44 of intermediate rail, and extending beneath and behind the downwardly depending ange 28 of the case rail. Normally, when load is applied to t-he special member 56 in cantilever fashion to the drawer rail, the rails will not become disassembled but will be retained in operative relationship. The back of panel 20 is secured to the cabinet, and the drawer is mounted on cantilever ange 56.

The square raceway configuration, and the opposed Iloading characteristics on a horizontal axis and a vertical axis of each of the spherical members in the raceways, are uniquely cooperative with the cantilever loading ange 56 to which the drawer load L is applied to achieve the novel result. It will be realized that when load is applied as indicated by the arrow L in FIG. 3, the cooperative drawer rail and intermediate rail will create lateral horizontal and vertical loading on balls 68, 68 and 74, 74. The intermediate rail in turn applies lateral loads and vertical loads on balls 62, 62 and 80, 80. All of these rails are thereby retained in exact vertical aligned Vrelationship under load yet without requiring especially close tolerances in the manufacture of these parts. There is completely adequate side clearance, yet with no significant lateral sway resulting. The rail members themselves are retained completely out of Contact with each other to prevent scraping and friction.

The same cantilever loading principle can be employed with slightly differently configurated rail members. More specifically, the modified rail assembly illustrated in FIG. 4 includes a case rail 112, an intermediate rail 114, and a drawer rail 116. These rail members telescopically interiit to form a plurality of four raceways, each having a square cross sectional configuration of two opposite vertical walls of two different rail members contacting the spherical balls with bearing surfaces on opposite sides, to form a horizontal load axis, and two opposite horizontal walls contacting the spherical elements on top and bottom, to form vertical load axes. The overall coniguration of the drawer rail member 116 is substantially like that illustrated in the rst form of the invention, but it is assembled in different relationship with the intermediate rail. That is, its horizontal ange extends between the lowermost raceway and the next raceway thereabove, rather than between the two central raceways as in the first form of the invention. The intermediate rail is shaped differently than in the iirst for-m of the invention, having a generally C-shaped lower portion, and a backwards C-shaped upper portion integral therewith. The case rail basically is still C-shaped in cross sectional configuration, but having two upwardly extending anges on the two legs of the C, rather than downwardly extending fianges.

The drawer rail 116 has two vertical panels which form two walls of two respective adjacent raceways, one horizontal panel which forms the bottom of one raceway and the top of a second raceway, and a horizontal inwardly extending cantilever loading flange 158 for mounting of a drawer. The case rail includes a main vertical back panel 120, an inwardly extending upper panel 121, the upper surface of which :for-ms the bottom of a raceway, and an upwardly extending outer flange 123 forming the inside of the same raceway. It also includes a lower inwardly extending horizontal leg panel 126 and an upwardly extending flange 127.

Drawer rail 116 includes a vertical panel 150, the cantilever support panel 158, an outwardly extending horizontal panel 152 and a vertically extending panel 154, these latter two forming a lbottom and side of a raceway. Intermediate rail 114 includes an upper backwardly positioned C-shaped portion with an upper horizontal leg 131, the bottom of which forms the top of a raceway, a vertical leg 133 forming one side wall of a raceway, and the lower leg 135 forming the bottom of another raceway. This lower leg has attached theretol an L-shaped member 137 which forms the top of 'a third raceway, as well as the inside wall thereof. Extending integrally downwardly from this leg 135 is a vertical leg 137 forming the wall of the lowermost raceway, and a horizontal leg 139 forming the bottom of the lowermost raceway. If desirable, a progressive actuating roller member 151 may be mounted on its horizontal axis to the intermediate rail, with the upper surface contacting the drawer rail, and the lowermost portion of the case rail for progressive actuation of the rails during extension and contraction. Two balls are mounted in each of the raceways as illustrated in FIGS. 4 and 5, similar to the first form of the invention.

Balls 162 and 162 are in raceway 160, balls 168 and 168 in raceway 166, balls 174 and 174 in raceway 172, and balls 180 and 180 in raceway 178.

In operation, one bottom edge of the drawer D is mounted on the cantilever support flange 158. The case rail is mounted to the cabinet C as indicated, so that, with the case rail supported against torsional deflection under the torsional forces applied with cantilever loading, the cantilever loading on the drawer rail causes lateral horizontal thrust on horizontal axes across the spherical rollers and vertical load thrust across the vertical axes of the rollers for maintained alignment and absence of side sway.

In operation, both of these novel drawer rail assemblies illustrated have been found to work effectively. Either of the assemblies enable drawers to be Imounted off horizontal, even on an angle of up to about 45 or so, without side sway, without binding, without scraping between the rail members, and with smoothness and quietness of operation. The lateral loads applied with drawer tilting are not detrimental as they normally are, since lateral loads are already applied on the novel assembly, and merely help stabilize the apparatus.

The assembly is believed to be a substantial advance over the rail assemblies known heretofore. It is conceivable that certain additional modifications of individual rail construction may be achieved within the concept presented. It will be realized that the concept employs the cantilever loading plus the horizontal and vertical axis loading of individual balls as the core of the unique operation. Hence, the invention is intended to be limited only by the scope of the appended claims and the reasonably equivalent structures to those defined therein.

I claim:

1. A drawer rail assembly comprising: telescopically interlitting rails including at least a drawer mounting rail and a case rail; each of said rails having adjoining fiat horizontal and vertical portions providing load-bearing surfaces; each pair of said adjoining portions disposed opposite another pair of adjoining horizontal and vertical portions of another of said rails to form a plurality of vertically spaced raceways of generally square cross section; roller means in each of said raceways, each having oppositely disposed upper and lower bearing surfaces and oppositely disposed side bearing surfaces; said drawer mounting rail having a horizontal one of said portions engaging the top of a first one of said roller means and also having a pair of said vertical portions, one engaging at least one side bearing surface of said first roller means and the other engaging an oppositely positioned side bearing surface of a second roller means located in a raceway which is vertically spaced from that of said first roller means, such that said drawer rail when loaded by the weight of a drawer acts as a moment arm to push on said first and second roller means in opposite horizontal directions; said first and second roller means when so pushed acting on the other of said vertical rail portions forming the raceways for such roller means to transfer the horizontally-directed pushing force to the respective rail of which such other portions are a part; each of said roller means in said assembly positioned in contact with both the horizontal and the vertical rail portions forming the raceway for such roller means when said drawer rail is under load; each of said rails in said assembly arranged such that when said drawer rail is under load at least one of said vertical portions in each of said raceways pushes on the roller means in that raceway horizontally toward the other vertical rail portion of that raceway.

2. The drawer rail assembly of claim 1, wherein said vertical portions of said drawer mounting rail in said pair thereof extend in opposite directions from said horizontal portion of such rail, said second roller means and said raceway therefore being located above said first roller means and its said raceway.

3. The drawer rail assembly of claim 1, including at least one intermediate rail in addition to said drawer rail and lcase rail, said intermediate rail interftting telescopically generally between said drawer and case rails, said intermediate rail having fiat horizontal and vertical portions defining load-bearing surfaces disposed opposite from like portions of both said drawer and case rails to form lcertain of said vertically spaced square raceways, said certain raceways having roller means therein which when said drawer rail is under load receive both horizontal and vertical loading and transfer such loading from said drawer rail to said case rail.

V4. The drawer rail assembly of claim 3, wherein said Vertical portions of said drawer mounting rail in said pair thereof extend in opposite directions from said horizontal portion of such rail, said second roller means and said raceway therefore being located above said first roller means and its said raceway.

5. The drawer rail assembly of claim 4, wherein said intermediate rail has a cross-sectional shape including a first vertical portion near the bottom, a first horizontal portion extending laterally of said first vertical portion above said bottom, a second vertical portion extending upwardly lfrom said first horizontal portion, a second horizontal portion extending laterally of said second vertical portion, and a third vertical portion extending downwardly from said second horizontal portion generally parallel to and spaced from said second vertical portion.

6. The drawer rail assembly of claim 5, wherein said case rail has a cross-sectional shape including a first horizontal portion near the bottom thereof, a first vertical portion extending upwardly from said first horizontal portion, a second horizontal portion extending laterally from said first vertical portion and disposed generally parallel to said first horizontal portion, and a second vertical portion extending downwardly from said second horizontal 7 8 portion spaced from and generally parallel to said rst 3,009,755 11/ 1961 Rackow 312-339 vertical portion. 3,203,749 8/1965 Bullock et al 312-339 References Cited FREDERICK L. MATTESON, IR., Primary Examiner.

UNITED STATES PATENTS 5 R, A. DUA, Assistant Examiner.

1,135,235 4/1915 Weiss 312-339 1,566,307 12/1925 card 312-339 US-C1XR 2,812,222 11/1957 Gussack 308-6 30S-3.8 

